# frozen_string_literal: true

# ViewModel used on Summary tab on User page

class UserSummary
  MAX_SUMMARY_RESULTS = 6
  MAX_BADGES = 6

  alias read_attribute_for_serialization send

  def initialize(user, guardian)
    @user = user
    @guardian = guardian
  end

  def topics
    Topic
      .secured(@guardian)
      .listable_topics
      .visible
      .where(user: @user)
      .order("like_count DESC, created_at DESC")
      .limit(MAX_SUMMARY_RESULTS)
  end

  def replies
    post_query
      .where("post_number > 1")
      .order("posts.like_count DESC, posts.created_at DESC")
      .limit(MAX_SUMMARY_RESULTS)
  end

  def links
    TopicLink
      .joins(:topic, :post)
      .where(posts: { user_id: @user.id, hidden: false })
      .includes(:topic, :post)
      .where("posts.post_type IN (?)", Topic.visible_post_types(@guardian && @guardian.user))
      .merge(Topic.listable_topics.visible.secured(@guardian))
      .where(user: @user)
      .where(internal: false, reflection: false, quote: false)
      .order("clicks DESC, topic_links.created_at DESC")
      .limit(MAX_SUMMARY_RESULTS)
  end

  class UserWithCount < OpenStruct
    include ActiveModel::SerializerSupport
  end

  def most_liked_by_users
    likers = {}
    UserAction
      .joins(:target_topic, :target_post)
      .merge(Topic.listable_topics.visible.secured(@guardian))
      .where(user: @user)
      .where(action_type: UserAction::WAS_LIKED)
      .group(:acting_user_id)
      .order("COUNT(*) DESC")
      .limit(MAX_SUMMARY_RESULTS)
      .pluck("acting_user_id, COUNT(*)")
      .each { |l| likers[l[0]] = l[1] }

    user_counts(likers)
  end

  def most_liked_users
    liked_users = {}
    UserAction
      .joins(:target_topic, :target_post)
      .merge(Topic.listable_topics.visible.secured(@guardian))
      .where(action_type: UserAction::WAS_LIKED)
      .where(acting_user_id: @user.id)
      .group(:user_id)
      .order("COUNT(*) DESC")
      .limit(MAX_SUMMARY_RESULTS)
      .pluck("user_actions.user_id, COUNT(*)")
      .each { |l| liked_users[l[0]] = l[1] }

    user_counts(liked_users)
  end

  REPLY_ACTIONS = [UserAction::RESPONSE, UserAction::QUOTE, UserAction::MENTION]

  def most_replied_to_users
    replied_users = {}

    post_query
      .joins(
        "JOIN posts replies ON posts.topic_id = replies.topic_id AND posts.reply_to_post_number = replies.post_number",
      )
      .joins(
        "JOIN topics ON replies.topic_id = topics.id AND topics.archetype <> 'private_message'",
      )
      .joins(
        "AND replies.post_type IN (#{Topic.visible_post_types(@user, include_moderator_actions: false).join(",")})",
      )
      .where("replies.user_id <> posts.user_id")
      .group("replies.user_id")
      .order("COUNT(*) DESC")
      .limit(MAX_SUMMARY_RESULTS)
      .pluck("replies.user_id, COUNT(*)")
      .each { |r| replied_users[r[0]] = r[1] }

    user_counts(replied_users)
  end

  def badges
    @user.featured_user_badges(MAX_BADGES)
  end

  def user_id
    @user.id
  end

  def user
    @user
  end

  def user_stat
    @user.user_stat
  end

  def bookmark_count
    Bookmark.where(user: @user).count
  end

  def recent_time_read
    @user.recent_time_read
  end

  class CategoryWithCounts < OpenStruct
    include ActiveModel::SerializerSupport
    KEYS = %i[
      id
      name
      color
      text_color
      style_type
      icon
      emoji
      slug
      read_restricted
      parent_category_id
    ]
  end

  def top_categories
    post_count_query = post_query.group("topics.category_id")

    top_categories = {}

    Category
      .where(
        id: post_count_query.order("count(*) DESC").limit(MAX_SUMMARY_RESULTS).pluck("category_id"),
      )
      .pluck(
        :id,
        :name,
        :color,
        :text_color,
        :style_type,
        :icon,
        :emoji,
        :slug,
        :read_restricted,
        :parent_category_id,
      )
      .each do |c|
        top_categories[c[0].to_i] = CategoryWithCounts.new(
          Hash[CategoryWithCounts::KEYS.zip(c)].merge(topic_count: 0, post_count: 0),
        )
      end

    post_count_query
      .where("post_number > 1")
      .where("topics.category_id in (?)", top_categories.keys)
      .pluck("category_id, COUNT(*)")
      .each { |r| top_categories[r[0].to_i].post_count = r[1] }

    Topic
      .listable_topics
      .visible
      .secured(@guardian)
      .where("topics.category_id in (?)", top_categories.keys)
      .where(user: @user)
      .group("topics.category_id")
      .pluck("category_id, COUNT(*)")
      .each { |r| top_categories[r[0].to_i].topic_count = r[1] }

    top_categories.values.sort_by { |r| -(r[:post_count] + r[:topic_count]) }
  end

  delegate :likes_given,
           :likes_received,
           :days_visited,
           :topics_entered,
           :posts_read_count,
           :topic_count,
           :post_count,
           :time_read,
           to: :user_stat

  protected

  def user_counts(user_hash)
    user_ids = user_hash.keys

    lookup = UserLookup.new(user_ids)
    user_ids
      .map do |user_id|
        lookup_hash = lookup[user_id]

        if lookup_hash.present?
          primary_group = lookup.primary_groups[user_id]
          flair_group = lookup.flair_groups[user_id]

          UserWithCount.new(
            lookup_hash.attributes.merge(
              count: user_hash[user_id],
              primary_group: primary_group,
              flair_group: flair_group,
            ),
          )
        end
      end
      .compact
      .sort_by { |u| -u[:count] }
  end

  def post_query
    Post
      .joins(:topic)
      .includes(:topic)
      .where(
        "posts.post_type IN (?)",
        Topic.visible_post_types(@guardian&.user, include_moderator_actions: false),
      )
      .merge(Topic.listable_topics.visible.secured(@guardian))
      .where(user: @user)
  end
end
